Karyotypes& Chromosome Mutations

Look at the karyotype for the mutation

A karyotype is an organized profile of a person's chromosomes. In a karyotype, chromosomes are arranged and numbered by size, from largest to smallest.

Karyotypes are done by doctors to diagnose some genetic disorders

A normal human karyotype has 46 chromosomes (23 pairs): #1-22 are called autosomes #23 are called sex chromosomes

XX~ female XY~ male

RECALL…What is a mutation? Any mistake or change in DNA sequence Mutations can only be inherited if they occur in sex cells Two types: Gene or chromosomal

Chromosomal mutation: affects whole or part of a chromosome Gene mutation: Changes to the bases in the DNA of ONE gene

Chromosomal Mutations Change in # of chromosomes OR structure of the chromosome Abnormality detected on karyotype Five types

Can YOU spot the chromosomal mutation??

1) Deletion Loss of all or part of a chromosome

2) Duplication Produce extra copies of parts of a chromosome.

3) Inversion Part of a chromosome breaks out and reinserts backwards.

4) Translocation Part of a chromosome breaks off & attaches to another chromosome

5) Nondisjunction Improper separation of homologous chromosomes during meiosis Results in extra or missing chromosomes in gametes

Remember—normally have 2 copies of each Types of Nondisjunction Trisomy~ 3 copies of a chromosome Monosomy~ 1 copy of a chromosome Remember—normally have 2 copies of each

Can you spot the mutation?

Down Syndrome – Trisomy 21 Intellectual and developmental disabilities may have heart defects and respiratory problems

2. Look at the karyotype for the mutation

Trisomy 18 (Edwards syndrome) abnormal brain function that is very severe Heart, Kidney, intestinal problems Severe developmental delays usually die within 1-2 years old http://www.trisomy18.or g/

3. Look at the karyotype for the mutation

Trisomy 13 (Patau syndrome) Extra fingers or toes Cleft lip or palate, Close set eyes, Scalp defects Problems with heart and brain structure die within 1-2 years old http://www.livingwithtri somy13.org/

4. Look at the karyotype for the mutation

Trisomy on Sex Chromosomes XYY Syndrome – Extra Y normal appearance, may be taller than average, delayed development of speech and motor skills, not likely to be inherited http://ghr.nlm.nih.gov/condition/47xyy-syndrome XXX Syndrome – Triple X normal appearance, may be taller than average, delayed development of speech and motor skills, not likely to be inherited, sometimes sterile/infertile http://ghr.nlm.nih.gov/condition/triple-x-syndrome

5. Look at the karyotype for the mutation

Klinefelter’s Syndrome – XXY Sterile/infertile, normal appearance May be taller than average May have less body or facial hair delayed development of speech and motor skills NOT more inclined toward homosexuality or bisexuality http://www.genetics.com.au/pdf/factshe ets/fs31.pdf

6. Look at the karyotype for the mutation

Monosomy Missing part or all of second X chromosome Turner Syndrome – X Missing part or all of second X chromosome usually sterile/infertile Shorter than average height, heart and kidney problems, Normal intelligence 99% embryos miscarriage or stillborn http://www.nfxf.org/html/what.htm

Look at the karyotype for the mutation

What is the mutation? Boy or Girl?

Trisomy 18

Trisomy 13 (Patau syndrome) Extra fingers or toes Cleft lip or palate (deformed lips) Heart and brain structure problems Die within 1-2 years of age

Trisomy on Sex Chromosomes XYY Syndrome – Extra Y Males only, taller than average, learning disabilities, behavior issues XXX Syndrome – Triple X Female only, Delayed learning ability, low speech abilities, Hit milestones slower

What is the mutation? Boy or Girl?

Turner’s Syndrome 45,X Webbed neck Infertile Swollen hands & feet at birth Heart defects

Chromosomal Mutations Videos Visualizing Nondisjunction